Re: AVR32 architecture patch against Linux 2.6.18-rc1 available

David Woodhouse
2006-07-06T23:16:57Z

On Thu, 2006-07-06 at 20:48 +0200, Haavard Skinnemoen wrote:
> > With MMIO those are just a not-so-special case of memory-memory,
> > surely? If the new framework doesn't support that, it probably
> > _should_.
>
> Yes, but there are at least two important differences:
>
> * Hanshaking. The DMA controller must know when the peripheral has
> new data available/is able to accept more data. Thus, you need to
> specify which set of handshaking signals to use as well as which
> direction the data is moved.
> * One of the pointers often stays the same during the whole transfer.

Those are hardly esoteric features -- the same goes for just about every
sane DMA controller on every architecture already. Any "generic DMA
framework" which isn't entirely crack-inspired is surely going to handle
it properly.

--
dwmw2